It is frequently necessary in a packaging operation or the like to move a succession of objects between two locations which not only are offset to one another spatially because of the types of processing equipment involved, but to which the objects arrive and from which they exit at different rates. For instant in a pill-making plant a stamping or similar device will deliver bubble packs of pills with their flat sides vertical to an intake location from which they must be moved to an output location, for instance a conveyor belt or chute, where they must be deposited flat side horizontal. Thus the packages must be held securely as they are swung through about 90.degree. between when they are picked up and when they are dropped off.
U.S. Pat. No. 4,211,153 to Walters and German patent document No. 2,922,171 filed 31 May 1979 by Rolf Andra describe such transfer conveyors which move objects between two adjacent locations. In the Walters device a plurality of suction cups are mounted on a carousel rotatable about a horizontal axis. These cups can move radially and angularly of the wheel in S-shaped tracks as the wheel rotates to bring the cups to a dead stop as they pick up and drop off a carton, passing through an intermediate position in which a flattened carton is broken open. In the device of Andra another such carousel carries a plurality of such suction cups, but they are not movable on the carousel. Instead the carousel is rotated by a step-type drive and is moved by another actuator toward and away from the pickup location where it pulls a bubble pack of pills from the machine that stamps it from a continuous strip of such pills to the output location where the individual bubble pack is dropped on an output conveyor.
Another arrangement seen in German patent document No. 2,923,909 filed 12 June 1978 by Otto Weller has another such carousel but carrying the suction grippers by means of complex lever-type linkages that allow these grippers to move relative to the carousel so they can move radially inwardly at least as the object, here a carton to be broken open, is pulled from the supply.
All these arrangements have the considerable disadvantage that the mechanism effecting the desired motion is extremely complex and acts in a jerky, normally reciprocating manner. Thus the parts are subject to substantial stress and have a short service life.